Electrical connectors – Metallic connector or contact having movable or resilient... – Screw-thread operated securing part
Reexamination Certificate
2000-10-05
2002-09-17
Bradley, P. Austin (Department: 2833)
Electrical connectors
Metallic connector or contact having movable or resilient...
Screw-thread operated securing part
C439S736000, C439S431000
Reexamination Certificate
active
06450842
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a terminal connector used in electrical systems, particularly in audio and video equipment systems. The present invention also relates to a method of fabricating the terminal connector.
2. Description of the Related Art
Referring to
FIG. 5
, a conventional terminal connector, shown generally at
100
′, includes an electrically conductive terminal plate
14
mounted on an insulative circuit board
10
. A terminal
15
is secured to insulative circuit board
10
by a screw portion
17
threaded through a screw hole
16
in terminal plate
14
. A knob
19
, affixed projecting away from terminal
15
enables screwing and unscrewing of screw portion
17
for making electrical connection, as will be explained.
A cylindrical portion
11
, surrounding a part of terminal
15
near a first surface of insulative circuit board
10
and helps avoid lead wire shorts and reduces the chance of electrical contact with a person or an object. Knob
19
of terminal
15
also protrudes away from the first surface. Cylindrical portion
11
has at least one lead wire insertion notch
12
in its outer periphery.
A through hole
13
accommodates adjustable screw portion
17
of terminal
15
. Screw portion
17
is centered in cylindrical portion
11
. Around through hole
13
a plurality of insertion holes
20
permit insertion of one or more press-in lock pieces
21
and a terminal portion
22
of terminal plate
14
into selected insertion holes
20
to fix terminal plate
14
firmly to insulative circuit board
10
.
Referring now also to
FIG. 6
, terminal body
59
′ made from electrically conductive material. Terminal body
59
′ has a cylindrical plug connection portion
23
, suitable for accepting the insertion of a conventional banana tip, a wire end, or other conductor. A collar
18
is pulled down into stabilizing contact with insulative circuit board
10
when screw portion
17
is tightened. The rim of collar
18
is partially removed to form a pair of anti-slip flats
28
for preventing rotation of terminal body
59
′ with respect to covering knob
19
.
Terminal body
59
′ is conventionally formed by cold forging, i.e. compressing a metal material between dies at temperatures not higher than the material's recrystallization temperature. Through cold forging, conventional cylindrical plug connection portion
23
, collar
18
, and screw portion
17
are simultaneously formed. Screw portion
17
and flats
28
are not readily formed by cold forging, and are therefore conventionally machined in a subsequent step.
Referring to
FIG. 5
, knob
19
is generally cylindrical in shape. A fit hole
25
, shaped to receive plug connection portion
23
, passes through the center of knob
19
. A plug insertion opening
26
, having a diameter greater than that of fit hole
25
, is formed at the top of fit hole
25
. A non-circular collar fit-in recess
24
at the bottom of fit hole
25
engages collar
18
, including flats
28
.
During assembly, plug connection portion
23
of terminal
15
is inserted into fit hole
25
from below. Then, collar
18
is fitted into collar fit-in recess
24
. The top of plug connection portion
23
is deformed outward, by swaging or other process, to create a bent portion
27
. Thus, terminal body
59
is engaged and integrally fixed in knob
19
by bent portion
27
and collar
18
.
When screw portion
17
, of terminal
15
, is tightened in screw hole
16
in terminal plate
14
, a bottom surface of collar
18
and the top surface of terminal plate
14
sandwich a lead wire (not shown) for electric contact. A banana plug (not shown) may be inserted in plug connection portion
23
of terminal
15
for electric connection. More than one lead wire may be captured in this way, and connected to a conductor inserted into plug connection portion
23
and/or terminal portion
22
.
Conventional terminal connectors have had several problems, particularly concerning the configuration and the fabrication method of terminal body
59
′.
Conventional terminal body
59
′, cannot be fabricated in a single step of cold forging. Therefore, removing part of the above-described collar
18
to form flats
28
requires an additional step. This increases manufacturing cost.
Fabrication by cold forging has advantages including, no waste chip production, exact dimensions, and higher product strength. However, since cold forging is a difficult fabrication method, cold forging can be used to fabricate the terminal body
59
′ only in limited production facilities. Accordingly, when fabrication by cold forging is employed, is desirable that the entire terminal body
59
′ be formed in a single step to limit transportation costs.
Assembly of conventional terminal body
59
′, requires collar
18
to be positioned individually in collar fit-in recesses
24
. Since collar fit-in recess
24
and corresponding collar
18
with flats
28
both have non-circular shapes, assembly must proceed slowly.
In addition, assembly of conventional terminal body
59
′ and knob
19
cannot be carried out by automatic assembly machine because of the additional individual positioning that is required. As a consequence, increased man-hours are required for assembly.
Incorrect assembly positioning may cause deformation of the peripheries of collar fit-in recesses
24
and corresponding insufficient anti-slip function during assembly. Such deformations may result in unacceptably high rejection rates, with consequent cost increases.
As discussed above, the conventional fabrication steps of terminal body
59
′ and later assembly with knob
19
require expensive labor and effort thus increasing fabrication costs and increasing anti-slip failures.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a terminal connector providing an anti-slip function.
It is a further object of the present invention to provide a terminal connector with simple construction.
It is a further object of the present invention to provide a method of single-step fabrication for a terminal body.
It is a further object of the present invention to provide a method of assembling a terminal and allowing anti-slip function without pre-positioning the terminal body.
The present invention relates to a forged terminal body and a resin knob assembled without pre-positioning. Anti-slip projections on the terminal body penetrate the knob during assembly to resist torque during connection. The anti-slip projections have asymmetric triangular cross sections with a steeper side of the triangle facing in the tightening direction. In one embodiment of the invention, the anti-slip projections are prismatic projections radially arranged on a collar. In a second embodiment of the invention, the anti-slip projections extend from the collar along a terminal body upon which the resin knob is press fitted.
According to an embodiment of the invention there is provided a terminal connector comprising: a circuit board, a terminal plate attached to the circuit board, a terminal threadable to the terminal plate allowing adjustment relative to the circuit board, the terminal being a terminal body and a knob covering part of the terminal body, the terminal body with a plug connection portion opposite a screw portion, the terminal body also containing a collar and at least one anti-slip projection, the knob having a fit hole and a collar fit-in recess; the plug connection portion in the fit hole and the collar in the collar fit-in recess engaging the anti-slip projection in the knob.
According to an another embodiment of the invention there is provided a terminal connector further comprising: at least one anti-slip projection having an acute profile arranged radially on the collar on the first side of the collar.
According to another embodiment of the invention there is provided a terminal connector further comprising: at least one anti-slip projection having an acute profile arranged radia
Mano Nobuyuki
Matsuda Takeshi
Bradley P. Austin
Darby & Darby
León Edwin A.
SMK Corporation
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